The research outlined in this proposal deals with the mechanisms of pituitary hormone control during reproductive states in female rats primarily. The role of hypothalamic biogenic amines, including dopamine, norepinephrine, and serotonin is being investigated. In addition, how these biogenic amines interact with the neuropeptides that control pituitary function is being studied. The reproductive conditions being investigated include; estrous cycle, pregnancy, pseudopregnancy, lactation, and steriod treatment.